Grammarly for Microsoft Word stopped working. I got this message:
Add-in Information: Microsoft 365 has been configured to prevent individual acquisition and execution of Office Store Add-ins.
Trying to re-add it gave me this message:
Office Store not available: Unfortunately, your organization has disabled access to the Office Store. Please contact your administrator to request access.
1. My university said that they knew nothing about blocking add-ins and sent me from team to team, and we got nowhere.
2. Grammarly was working on one of my other computers but not on my main MacBook Pro or on other staff MBPs.
3. I completely uninstalled Office (including deleting container files in ~Library) and reinstalled. This did not work.
4. I went to Word/Sign Out and signed out; the Grammarly add-in could be installed.
a. Signing back in to Microsoft 365 blocked Grammarly.
b. Signing out again restored its use.
Since Word seems to work perfectly fine when I am signed out, I will leave it that way. If I need to sign in for some reason, I now know that signing out restores Grammarly's functioning.
This took me hours to figure out, so I hope that posting it here might save others some time.